A particularly troubling aspect of enterprise computer deployment is the need for end user machines to remain switched on day and night. Fully on mind you, not in low power sleep mode. Computer scientists from the University of California, San Diego have developed a software solution which allows PCs to remain on the network even when placed in sleep mode at the end of a working day. The software creates a virtual representation of the computer on the server to handle many of the common overnight tasks, only waking up the physical machine at pre-programmed commands or when it encounters something that it can't deal with itself.

Dubbed "sleep-working" by the scientists who created the SleepServer software, the solution ensures that PCs remain connected and available on a network even after users have placed the machines in low-power mode. The software creates a lightweight virtual image of each computer in an enterprise environment. When a user places a machine in sleep mode at the end of a working day, the SleepServer software activates and the virtual PC image masquerades as the physical PC on the server, responding to network events on behalf of the dozing computer.

The virtual PC takes care of such things as Voice over IP commands, instant messaging and peer-to-peer services and caters for remote access to the PC via such protocols as VPN, SSH encrypted connection and Remote Desktop. It differs from existing solutions in that the physical machine's slumber is only interrupted when a network request is received which the lightweight image can't deal with. The solution is scalable and compatible with existing network infrastructures, it also enjoys cross platform support, although a MAC OSx version is still in development.

"One of the big benefits of SleepServer is configurable on-demand wakeup. SleepServer enables enterprise PCs to remain asleep for long periods of time while still maintaining the illusion of network connectivity and seamless availability," explained Yuvraj Agarwal, the UC San Diego Research Scientist in the Department of Computer Science and Engineering who developed SleepServer.

Another benefit is the projected energy savings, which have been shown to be anywhere between 27 and 86 per cent according to a recent survey. During a test run in September 2009, the power consumption of 30 PCs running SleepServer dropped by an average of 60 per cent, when compared to leaving the machines fully powered on day and night. The solution is said to offer an average yearly saving per PC of US$60 and deployment across department or office environments could therefore result in considerable energy savings.

There are currently over 50 computers using the solution at the University of California, San Diego's computer science building, Agarwal claiming that he has "seen an almost 70 per cent energy savings on my PC over the last six months." Plans are in place to expand the solution across the remaining thousand or so machines in the department by the end of the year, and then onto the entire campus network thereafter.

Agarwal said: "We are a very heterogeneous department. If SleepServer can support the diverse computing needs of the computer science department, it should be able to support anyone. Most enterprises don't have eight different versions of operating systems running at the same time."